In order to construct concrete columns, piers and footings, it is generally necessary to utilize a concrete form. The form act as a mold for pouring concrete to provide a desired size and shape. Among available forms are spirally-wrapped fiber forms, steel sectional forms and fiberglass forms. Fiber forms are generally single-piece cylindrical forms of a select diameter. The form can be cut to length on a job site, erected, braced, and stripped quickly and easily. As such, these forms are not reusable. Also, the fiber forms are less desirable when used in wet areas, and also leave helical seams on the finished concrete column.
Steel forms generally comprise half round sections bolted into units. Each section comprises a semi-cylindrical wall framed with flange angles die cut and punched for flush butt joints. Vertical and horizontal seams are connected with bolts. A plurality of similar or different length sections can be stacked together according to the necessary column height. Some of the problems with steel sectional forms include heavy weight, expensive production, and the possibility of rusting of the steel. Also, grout leakage can occur where the flanges abut, which degrades the appearance of the finished concrete column.
Fiberglass forms have also been used in half-round sections, as with steel form sections. However, such fiberglass sections lack uniformity in wall and flange thickness and do not stack as well. Further, fiberglass flanges require steel backing where bolts are used for securing sections together. One known form of such fiberglass forms utilizes tongue and groove vertical flanges to minimize vertical seams in the concrete columns. However, problems still remain owing to possible horizontal seams.